Polyamide resins are generally produced by polymerization reaction between diamines and activated dicarboxylic acids. However, such processes require separation of by-products after polymerization. Processes for production of polyamide resins that require no separation of by-products after polymerization are known, which involve reaction between dicarboxylic acids and diisocyanates (for example, see Patent document 1).
Processes for production of polyamide resins with reactive double bonds are also known, such as (1) introduction of a reactive double bond into polyamic acid (for example, see Patent documents 2 and 3), (2) polymerization of a diamine with maleic anhydride (for example, see Patent document 4), (3) addition of a hydrocarbon oligomer with double bonds to the end of a polyamide (for example, see Patent documents 5 and 6) and (4) introduction of a reactive double bond into polyaniline followed by polymerization with an acid chloride (for example, see Patent document 7).
A curable resin composition can be obtained by using a polyamide resin with a reactive double bond. For example, a photocuring resin composition containing a polyamide resin obtained by the production process of (1) can be cured by heating after patterning by light irradiation (for example, see Patent documents 2 and 3).
The isocyanate method is known as a process for production of polyamideimide resins. As specific examples there may be mentioned a method in which trimellitic anhydride is reacted with a diisocyanate, a method in which an aromatic tricarboxylic anhydride is reacted with an ether bond-containing diamine with an excess of an acid component, and then reacted with a diisocyanate (for example, see Patent document 8), and a method in which the reaction product of a diamine and a diisocyanate is reacted with trimellitic anhydride (for example, see Patent document 9).
These polyamideimide resins themselves do not have curing properties. When these polyamideimide resins are used to prepare curable resin compositions, therefore, it has been necessary to add a curing component. However, a greater amount of added components tends to result in loss of properties of the polyamideimide resins. Methods have therefore been investigated for preparing curable resin compositions using polyamideimide resins with functional groups for curing.
For example, there are known methods of preparing a thermosetting resin composition using a polyamideimide resin having epoxy groups introduced therein (for example, see Patent document 10), methods of preparing a photocuring resin composition using a polyamideimide resin having epoxy groups introduced at the molecular ends as a photosensitive resist (for example, see Patent document 11), and methods of preparing a curable resin composition using a polyamideimide resin having a reactive double bond introduced therein (for example, see Patent documents 12 and 13). As examples of methods of introducing a reactive double bond into a polyamideimide resin there are known methods wherein the polyamideimide site is copolymerized with the reactive double bond site (for example, see Patent document 12) and methods wherein the molecular ends are sealed with reactive double bonds (for example, see Patent document 13). There is also known a method wherein a photocuring resin composition containing a polyamide-amide acid with a reactive double bond is irradiated, patterned and then heated to form a polyamideimide resin (for example, see Patent document 14).    [Patent document 1] Japanese Unexamined Patent Publication HEI No. 06-172516    [Patent document 2] Japanese Patent Publication No. 2880523    [Patent document 3] Japanese Unexamined Patent Publication No. 2003-287889    [Patent document 4] Japanese Unexamined Patent Publication HEI No. 10-182837    [Patent document 5] Japanese Unexamined Patent Publication No. 2001-31759    [Patent document 6] Japanese Unexamined Patent Publication No. 2001-31760    [Patent document 7] Japanese Unexamined Patent Publication HEI No. 04-132733    [Patent document 8] Japanese Patent Publication No. 2897186    [Patent document 9] Japanese Unexamined Patent Publication HEI No. 04-182466    [Patent document 10] Japanese Unexamined Patent Publication HEI No. 11-217503    [Patent document 11] Japanese Unexamined Patent Publication HEI No. 10-204150    [Patent document 12] Japanese Unexamined Patent Publication No. 2000-344889    [Patent document 13] Japanese Unexamined Patent Publication HEI No. 10-316754    [Patent document 14] Japanese Patent Publication No. 2902761